Tension sensor assembly

ABSTRACT

A tension detector may detect and help correct tension in a lift cable. The cable may include a lift cable within a telescopic structure, such as a telescopic tower. The tension sensor may detect when the cable tension is outside a high tension threshold and a low tension threshold and trigger an alert when outside the thresholds. The alert may be an audible alert or a visual alert. A controller may prevent a user from making the tension worse and encourage an operator to correct the tension problem by preventing a winch from expanding or retracting the telescopic structure. The tension sensor may use springs to calibrate the thresholds for the high tension and low tension and a series of pulleys to manipulate an arm to engage a tension sensor.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims the priority benefit of U.S. provisionalpatent application 61/407,562, filed Oct. 28, 2010, and titled “TensionSensor Assembly (TSA)”, the disclosure of which is incorporated hereinby reference.

BACKGROUND

Telescoping towers may be raised and lowered by operators controlling anelectronic winch. When raising a telescoping tower using a winch, anoperator may raise a tower section into position on the tower and securethe tower section with safety locks at the top of the base section. Guycables may then be attached and tensioned to the first tower section.

Operators often make procedural mistakes when raising or lowering atelescoping tower section using a winch. For example, an operator mayfail to secure a first tower section with safety locks at the top of thebase section. As a result, guy cable tension may exert force against thewinch which may overwhelm the winch. In addition to causing high tensionconditions, operator error in using a winch may cause a low tensioncondition which could also damage the telescoping tower or supportingequipment.

What is needed is an improved system for managing tension in raising andlowering telescoping towers.

SUMMARY OF THE INVENTION

The present technology includes a tension detector may detect and helpcorrect tension in a lift cable. The cable may include a lift cablewithin a telescopic structure, such as a telescopic tower. The tensionsensor may detect when the cable tension is outside a high tensionthreshold and a low tension threshold and trigger an alert when outsidethe thresholds. The alert may be an audible alert or a visual alert. Acontroller may prevent a user from making the tension worse andencourage an operator to correct the tension problem by preventing awinch from expanding or retracting the telescopic structure. The tensionsensor may use springs to calibrate the thresholds for the high tensionand low tension and a series of pulleys to manipulate an arm to engage atension sensor.

An embodiment includes a tension sensor having a housing, a low tensionsensor mechanism, a high tension sensor mechanism, and an alertmechanism. The low tension sensor mechanism may be coupled to thehousing and configured to receive the lift cable. The high tensionsensor mechanism may be coupled to the housing and configured to receivethe lift cable. The alert mechanism provides an alert when the lowtension sensor mechanism detects a tension below a low tension thresholdor the high tension sensor mechanism detects a tension above a hightension threshold.

An embodiment includes a system for sensing tension. The system includesa telescopic structure, a lift cable, a winch and a tension sensor. Thewinch controls the movement of the lift cable in the telescopicstructure. The tension sensor receives the lift cable and detect when atension in the lift cable is outside a specified tension range.

An embodiment includes a method for sensing tension in a lift cable usedin a telescopic structure. The method may include operating a lift cableusing a winch controlled by a controller. The lift cable may beconfigured to raise and lower a telescopic structure, such that the liftcable having a tension sensor attached to the lift cable. A tension maybe detected in the lift cable by the tension sensor, the tension beingoutside a tension range. Triggering an alert by the tension sensor.

BRIEF DESCRIPTION OF DRAWINGS

FIG. 1 illustrates an exemplary system for sensing tension in a liftcable.

FIG. 2 illustrates an exemplary tension sensor for a cable having anormal tension.

FIG. 3 illustrates an exemplary tension sensor for a cable having a hightension.

FIG. 4 illustrates an exemplary tension sensor for a cable having a lowtension.

FIG. 5 illustrates an exemplary method for sensing tension in a cable.

FIG. 6 illustrates an exemplary method for triggering a high tensionalert.

FIG. 7 illustrates an exemplary method for triggering a low tensionalert.

DETAILED DESCRIPTION

The present invention detects tension in a cable. The cable may includea lift cable within a telescopic structure, such as a telescopic tower.The tension sensor may detect when the cable tension is outside a hightension threshold and a low tension threshold and trigger an alert whenoutside the thresholds. The alert may be an audible alert or a visualalert. A controller may prevent a user from making the tension worse andencourage an operator to correct the tension problem by preventing awinch from expanding or retracting the telescopic structure. The tensionsensor may use springs to calibrate the thresholds for the high tensionand low tension and a series of pulleys to manipulate an arm to engage atension sensor.

FIG. 1 illustrates an exemplary system for sensing tension in a liftcable. The system of FIG. 1 includes a telescopic structure 110, cablesupport 120, tension sensor 125, lift cable 115, and controller 130.Lift cable 115 extends from cable support 120 down the length of thetelescopic structure 110. The telescopic structure may be a telescopictower or other structure. A winch (not illustrated) may be used to raiseand lower the telescopic structure 110.

Controller 130 may be in communication with the winch and be used tooperate the winch to raise and lower the lift cable. Controller 130 mayinclude one a cable high tension visual sensor, cable low tension visualsensor, cable high tension audio sensor, controls for operating a winchcoupled to the lift cable, and other inputs and outputs. The controllermay include or control electric motors such as a tower winch. Thecontroller may be integrated into the tower or be implemented remotelyfrom the tower.

FIG. 2 illustrates an exemplary tension sensor 125 for a cable having anormal tension. The tension sensor of FIG. 2 may be used in the tensionsensing system of FIG. 1. Tension sensor 125 may include an assembly210, a low tension spring 215, a high tension spring 220, a high tensionarm 230, high tension pulleys 232 and 236, a high tension arm pivot 234,a high tension sensor 239, a low tension arm 240, a low tension pulley242, low tension arm pivot 244, low tension block 248, low tensionsensor 250, and idler pulley 260.

Lift cable 205 is routed below pulley 232 in a counter clockwisedirection and above pulley 236 in a clockwise direction. Lift cablecontinues below pulley 250 in a clockwise direction and above pulley 242in a counter-clockwise direction. Pulleys 232 and 236 are implemented onhigh tension bar 230 and pulley 242 is implemented on low tension bar240.

The thresholds for triggering an alert are determined tension springs.High tension spring is coupled to an end of high tension arm 230 nearpulley 236 and determines the threshold for triggering a high tensionalert. Low tension spring is coupled to an end of low tension arm 240near pulley above tension block 248 and determines the threshold fortriggering a low tension alert.

Alert panel 260 may provide a visual or audible alert in response to atension sensor being engaged. The alerts may be provided in place of orin addition to alerts generated on controller 130.

FIG. 3 illustrates an exemplary tension sensor for a cable having a hightension. When the tension applied to high tension pulleys 232 and 236 bylift cable 205 is great enough to overcome the tension applied to hightension pulleys 232 and 236 from high tension spring 220 (attached tohigh tension arm 230), high tension arm 230 rotates clockwise alongpivot 234 to engage high tension sensor 239.

When high tension sensor 230 is engaged, an alert is generated. Thealert may be an audio alert, a visual alert (such as an LED or a screenmessage), or both, indicating that the tension in the lift cable is toohigh. In response to the alert, controller 130 (FIG. 1) willautomatically prevent the winch from extending the telescopic structure.Preventing extension of the telescopic structure prevents furthertension increase and requires an operator to reduce the tension in thelift cable. When the high tension arm no longer engages the high tensionsensor 239 (is not longer in contact with the sensor), the controllermay allow the winch to extend the telescopic structure.

FIG. 4 illustrates an exemplary tension sensor for a cable having a lowtension. When the tension applied to low tension pulley 242 by liftcable 205 is small enough to be overcome by the tension applied to lowtension pulley 242 from low tension spring 215 (attached to low tensionarm 240), low tension arm 230 rotates clockwise along pivot 244 toengage low tension sensor 240.

When low tension sensor 240 is engaged, an alert is generated. The alertmay be an audio alert, a visual alert (such as an LED or a screenmessage), or both, indicating that the tension the lift cable is toolittle. In response to the alert, controller 130 (FIG. 1) willautomatically prevent the winch from retracting the telescopicstructure. Preventing retraction of the telescopic structure preventsfurther tension decrease and requires an operator to increase thetension in the lift cable. When the low tension arm no longer engagesthe low tension sensor 240 (is not longer in contact with the sensor),the controller may allow the winch to retract the telescopic structure.

FIG. 5 illustrates an exemplary method for sensing tension in a cable.The method of FIG. 5 may be performed by the system of FIG. 1. A tensionsensor is installed in a telescopic structure lift cable at step 510.Installing a tension sensor in a cable includes routing the cablethrough a series of pulleys within the tension sensor, as discussedabove with respect to FIG. 2.

An operator may operate a winch which controls the cable at step 520.The winch may be operated through controller 130. Operating the winchmay include retracting and extending the telescopic structure using thelift cable.

A determination is made as to whether a high tension alert is triggeredat step 530. A high tension alert may be triggered if the tension in thelift cable is greater than a threshold level. For example, tensioning atelescopic structure without locking structure portions in place maycreate a high tension. Determining whether a high tension alert istriggered is discussed in more detail below with respect to FIG. 6. Ifhigh tension alert is triggered at step 530, extending the telescopicstructure may be suspended until the high tension is reduced below thethreshold at step 540. For suspending the extension function of thetelescopic structure, an operator may only retract the telescopicstructure, which will reduce the high tension in the cable. The methodof FIG. 5 then continues to step 550. If a high tension alert is nottriggered, the method of FIG. 5 continues from step 530 to step 550.

A determination is made as to whether a low tension alert is triggeredat step 550. A low tension alert may be triggered if the tension in thelift cable is less than a threshold level. For example, attempting tolower a telescopic structure without unlocking structure portions inplace may create a low tension (slack in the cable). Determining whethera low tension alert is triggered is discussed in more detail below withrespect to FIG. 7. If low tension alert is triggered at step 550,retracting the telescopic structure may be suspended until the lowtension is increased to a point above the low tension threshold at step560. For suspending the extension function of the telescopic structure,an operator may only expand the telescopic structure, which willincrease the low tension in the cable. The method of FIG. 5 then ends.If a high tension alert is not triggered, the method of FIG. 5 ends.

FIG. 6 illustrates an exemplary method for triggering a high tensionalert. The method of FIG. 6 provides more detail for step 530 of themethod of FIG. 5. A determination is made as to whether a high tensionsensor detects a high tension arm at step 610. When tension is increasedin the lift cable which is routed through a tension sensor, the hightension arm rotates clockwise such that an arm end rotates close hightension sensor 239. If the high tension arm rotates clockwise andengages (e.g., touches) the high tension sensor, the high tension arm isdetected at step 610 and the method of FIG. 6 continues to step 620. Ifthe high tension arm does not engage the high tension sensor, the methodof FIG. 6 ends.

A high tension audio alert is generated at step 620. The high tensionaudio alert may be generated at the controller 130, the tension sensor210, and at other devices. A high tension visual alert is generated atstep 630. The visual alert may include a series of one or more lights orLEDs, a graphical display, or some other visual output device. Aftergenerating the high tension visual alert, the method of FIG. 6 ends.

FIG. 7 illustrates an exemplary method for triggering a low tensionalert. The method of FIG. 6 provides more detail for step 550 of themethod of FIG. 5. A determination is made as to whether a low tensionsensor detects a low tension arm at step 710. When tension is decreasedin the lift cable which is routed through a tension sensor, the lowtension arm rotates clockwise such that an arm end rotates towards lowtension sensor 250. If the low tension arm 240 rotates clockwise andengages (e.g., touches) the low tension sensor 250, the low tension armis detected at step 710 and the method of FIG. 7 continues to step 720.If the low tension arm does not engage the low tension sensor, themethod of FIG. 6 ends.

A low tension audio alert is generated at step 620. The low tensionaudio alert may be generated at the controller 130, the tension sensor210, and at other devices. A low tension visual alert is generated atstep 630. The visual alert may include a series of one or more lights orLEDs, a graphical display, or some other visual output device. Aftergenerating the high tension visual alert, the method of FIG. 6 ends.

The invention has been described herein in terms of several preferredembodiments. Other embodiments of the invention, including alternatives,modifications, permutations and equivalents of the embodiments describedherein, will be apparent to those skilled in the art from considerationof the specification, study of the drawings, and practice of theinvention. The embodiments and preferred features described above shouldbe considered exemplary, with the invention being defined by theappended claims, which therefore include all such alternatives,modifications, permutations and equivalents as fall within the truespirit and scope of the present invention

1. A tension sensor for use with a lift cable within a structure,comprising: a housing; a low tension sensor mechanism coupled to thehousing and configured to receive the lift cable; a high tension sensormechanism coupled to the housing and configured to receive the liftcable; and an alert mechanism for providing an alert when the lowtension sensor mechanism detects a tension below a low tension thresholdor the high tension sensor mechanism detects a tension above a hightension threshold.
 2. The tension sensor of claim 1, wherein the lowtension mechanism includes a low tension spring.
 3. The tension sensorof claim 2, wherein the low tension mechanism detects a tension belowthe low tension threshold when a pressure on a low tension arm is lessthan a tension provided by the low tension spring.
 4. The tension sensorof claim 3, wherein the low tension sensor mechanism includes a sensorthat triggers an alert when the low tension arm engages the sensor. 5.The tension sensor of claim 1, wherein the high tension mechanismincludes a high tension spring.
 6. The tension sensor of claim 5,wherein the high tension mechanism detects a tension above the hightension threshold when a pressure on a high tension arm is greater thana tension provided by the high tension spring.
 7. The tension sensor ofclaim 6, wherein the high tension sensor mechanism includes a sensorthat triggers an alert when the high tension arm engages the sensor. 8.The tension sensor of claim 1, wherein the alert mechanism provides anaudio alert indicating that a tension in the lift cable is outside thelow tension threshold or the high tension threshold.
 9. The tensionsensor of claim 1, wherein the alert mechanism provides a visual alertindicating that a tension in the lift cable is outside the low tensionthreshold or the high tension threshold.
 10. The tension sensor of claim1, wherein the lift cable is received by the tension sensor andcontrolled by an operator to raise and lower a telescopic tower.
 11. Asystem for sensing tension in a lift cable, comprising: a telescopicstructure; a lift cable; a winch controlling the movement of the liftcable in the telescopic structure; a tension sensor configured toreceive the lift cable and detect when a tension in the lift cable isoutside a specified tension range.
 12. The system of claim 11, whereinthe tension sensor triggers an alert when the tension in the lift cableis above a high tension threshold or below a low tension threshold. 13.The system of claim 11, wherein the alert is an audio alert.
 14. Thesystem of claim 11, wherein the alert is a visual alert.
 15. The systemof claim 11, further comprising a controller, the controller preventingthe lift cable from extending the telescopic structure in response todetecting a high tension alert.
 16. The system of claim 15, thecontroller preventing the lift cable from retracting the telescopicstructure in response to detecting a low tension alert.
 17. A method forsensing tension in a lift cable used in a telescopic structure, themethod comprising: operating a lift cable using a winch controlled by acontroller, the lift cable configured to raise and lower a telescopicstructure, the lift cable having a tension sensor attached to the liftcable; detecting a tension in the lift cable by the tension sensor, thetension being outside a tension range; and triggering an alert by thetension sensor.
 18. The method of claim 17, further comprisingautomatically preventing partial operation of the winch by thecontroller in response to the alert until the tension is within thetension range.
 19. The method of claim 17, wherein the alert is an audioalert or a visual alert.